F3-14900CL9D-8GBSR + Gigabyte 970a-D3 + 1100T BE x6

[tyhboom]

Hi All

I have 2 sets of F3-14900CL9D-8GBSR ram and I am having a tough time passing my stress test (prime95 blend) for more than 1 hour. At the 1 hour mark I get a fatal error in prime95 on at least one worker.

I am trying to get the 1866 mhz. I followed the instructions for the processor to get my desired clock speed. But still no dice on stability.

• Set NB to 2800
• CPU-NB Voltage to 1.3v
• DRAM timings 9 - 10 - 9 - 28 - 2t
• DRAM voltage 1.6v

CPU-Z screens


ADDED Bios Settings screens








Am I doing something wrong? I have completely down clocked my CPU to stock and I can't get a stable memory.

[Tradesman]

Any time you mix sets it can be problematic, even if they are the same exact model, it's worse if doing it on AMD and even worse at 1866 and above (sorry bout that, but that's the way it is, AMD has weak MCs (memory controllers). At 1866 you need a CPU OC, think I'd try raising the tRFC to 175 or so if it allows manual settings, RAS to RAS Delay 7T, Prechargs to 8T, TwTr Command Delay to 8T, Row Cycle Time 40T, Write Recovery Time 13T and the CPU/NB voltage to 1.35

[tyhboom]

The best I could do with my bios settings was

Trfc (0 and 1) 160ns (next step is 300ns)
RAS to RAS delay 7t
Precharge 7t
Twtr - 7t
Row cycle Time - 40t
Write recovery time - 12t
CPU - NB voltage - 1.35v

I put up a really modest OC on the processor
233 x 15.5 = 3600~

Everything booted fine with that. Will run torture test and report back results.

[tyhboom]

Nope instant fail on prime95...reaching for 1866 too much? Maybe I should just tone it down to 1600 and call it.

[Tradesman]

Yeah, might tone it back to 1600, get that good and stable then try taking it up..sometimes it's a good idea to back it down and give the brain a rest

[tyhboom]

Running at 1600 same timings as above NB freq 2400 CPU NB voltage 1.25 with CPU freq 3600 lasted 8 hours in prime95 blend. Guess I will just keep working from this point.

No super fast ram for me Maybe I'll try a single set sometime and see if it does better

[Tradesman]

AMD has a weak MC (Memory Controller) compared to Intel, AMD's newest, Highest end CPU, the FX-8350 is only rated UP TO 1866 at 1 stick per channel or 2 sticks total, below is a ratings guide AMD has buried on their web site:

http://support.amd.com/us/kbarticles...encyguide.aspx

[tyhboom]

That is a disappointing fact I will make due with what I got. Ram seems stable enough at 1600. I will play with timings to see what happens and move onto overclocking other things. Very Helpful information Tradesman!

[Tradesman]

Sorry we couldn't do more, there are some AMD gurus here that are in and out, maybe one will see something and offer a suggestion